数据库oracle/mysql多条重复数据,取最新的
MYSQL1、分组取最新的,再用最新的字段连表,回查数据
①按分组字段取最新的,通过主键id回表查数据
select * from table_name
WHERE id in (
select max(id) id from table_name GROUP BY 分组字段) ②非主键字段
SELECT r.*
FROM records r
INNER JOIN (
SELECT group_id, MAX(timestamp) as latest
FROM records
GROUP BY group_id
) as latest_records
ON r.group_id = latest_records.group_id
AND r.timestamp = latest_records.latest; ORACLE
1、原理解说-可直接看2
筛选出最新的
SELECT *
FROM (
SELECT t.*,
ROW_NUMBER() OVER (PARTITION BY LOCALAUTHID ORDER BY LASTUPDATETIME DESC) AS rn
FROM USER_LOCALAUTH_STATE t
) t
WHERE t.rn = 1; 解释:
这个序号是基于[LOCALAUTHID]字段举行分区的(即每个值都是一个新的分区),而且在每个分区内部,行是按照LASTUPDATETIME字段降序分列的
https://img-blog.csdnimg.cn/direct/69f7eca8d97349a59a1c34de1b4cc95e.png
2、在重复数据取最新的
SELECT *
FROM (
SELECT t.*,ROW_NUMBER() OVER (PARTITION BY LOCALAUTHID ORDER BY LASTUPDATETIME DESC) AS rn
FROM
(
-- 筛选存在重复的数据,count(LOCALAUTHID) > 1
select * from USER_LOCALAUTH_STATE
where LOCALAUTHID in (
SELECT LOCALAUTHID
FROM USER_LOCALAUTH_STATE WHERE STATE = 1 AND BUSINESSTYPE=1
group by LOCALAUTHID having count(LOCALAUTHID) > 1)
) t
) rt
WHERE rt.rn = 1; https://img-blog.csdnimg.cn/direct/30e44314aa2e4e0d8083903ff2178ca2.png
3、若要删除不满意条件
在2的基础上,通过查询,并删除ID不再2中的
https://img-blog.csdnimg.cn/direct/2d4e3e635fec4e3f98ea11b4675754f1.png
免责声明:如果侵犯了您的权益,请联系站长,我们会及时删除侵权内容,谢谢合作!更多信息从访问主页:qidao123.com:ToB企服之家,中国第一个企服评测及商务社交产业平台。
页:
[1]